Power connector sets used for high electric power connection generally consist of male and female connector members which are often provided with locking devices which interact between the two members to prevent accidental separation of the two members.
A standard type of lock is a bayonet lock where one of the members carries a key or projection which can be inserted into a groove or slot in the other member during coupling of the two members, the slot being L-shaped or J-shaped or otherwise configured. A known bayonet configuration is one that requires the key to move axially in the slot to a first axial position at or near an end of the slot before permitting rotation to occur and upon rotation requires, or allows, the key to undergo a slight axial movement in the opposite direction such that the key bearing connector cannot be rotated again with respect to the bayonet slot carrying member without the members undergoing relative axial movement towards one another.
The use of bayonet slots in coupling electrical connectors together is well known and is shown, for example, in U.S. Pat. No. 5,423,692 where a straight L-shaped bayonet slot is used which does not require retro axial movement to occur before rotation from the unlocked to the locked position.
While such bayonet connections are effective in preventing separation of the connector members when the key has been rotated into the circumferentially extending slot at the end of the axial entrance slot of the bayonet slot, they do not protect against unauthorized disconnection either intentionally or by vibration causing relative rotational movement between the connectors.
For this reason it has been proposed to provide a secondary lock which prevents the rotation of the key in the bayonet slot from its locked position in the absence of a determined secondary lock unlocking action. Preferably the determined unlocking action may require a tool to disengage the secondary lock. Such a combination of a bayonet slot and a secondary lock requiring use of a tool for intentional unlocking is shown, for example, in U.S. Pat. No. 5,685,730. The secondary lock as shown in that patent incorporates an axially spring biased pin in one of the connector members, which, upon rotation of the key in the bayonet slot, will project into a radially outer diameter open slot which is also open to an axial said face in the other member, the pin having a degree of projection less than the length of the radially open slot. The pin will prevent rotation of the two connector members by engagement of the pin with the walls of the slot. A pry tool can be used to abut the end of the pin in the slot to push it back against the spring and out of the open slot to allow rotation of the key member with respect to the bayonet slot member.
While the use of an axially projecting pin secondary lock overcomes many of the problems associated with unintentional disconnection of the connector set, it would be an improvement in the art to provide an alternative secondary locking member.